Sound transmitting and reproducing unit.



N. A. KUHMAN. SOUND TRANSMITTING AND EEPRODUCING UNITr ,Wm M fw j M, am,

.- n ASpecication of LettersviPatent.

f namen.

NATHAN A. KURNAN, or oAxLANncALIronNIA, AssmNoz,u BY msNIi ASSIGNMENTS, To INTEnNATroNAL cALLoPHoNE conronATIoN, orNnwzronx, N. Y.,A como :sATIoN or DELAWARE.. l 1

' SOUND G- AND REBIBQBUCIN'G-A UN Patented oct. 10,1916.

4 Application mea may s, 191s, serial No. wsaso. Renewed may 1s, 191e 1 semina. 98,439.

To all 'whom t may concern Be it known that I, NATHAN A. KURMAN, a citizen -of the United States, residing at Oakland, in the county of Alameda and State of California, have invented certain "new and useful Improvements, in .Sound Transmitting and -Reproducing Units, lof

which the following is a specification.

This invention relates to telephonic apparatus and has as its principal object the production of' a ombined unit adapted to act as both receiver and transmitter.

Alsecond object of the invention 'is to v"produce a transmitter adapted to be actuated by the voice/cfa person speaking 1n an ordinary tone anywhere within the room in which the instrument is-situated. l A -further object to increase the range in volume of the previous receiversxof the loud speaking type.

`The final object resides inthe particular arrangement and combination of partshereinafter described. l j

In the accompanying drawing -Figure 1 is a central longitudinal crosssectional view takenthrough a combined `transmitting and receiving unit embodying my improvement therein, and showing the same mounted in a horn. Fig. 2 is a sectiontaken on line 2 2 of Fig. 1 looking in the direction of the arrow. Fig. 3 is a central vertical longitudinal section showing the operating parts of my combined receiving and transmitting unit and taken on the'line'3 3 of Fig. 4. Fig. 4 is a cross sectional viewvtaken onthe line 4- 4 of Fig. 3, looking in the direction of the arrow. i

-In the separate views the same partis designated by the same reference character.

Referring more' particularly to the drawing, my improved loud speaking receiver or sound reproducer comprises, as shown in Figs. 3 and 4, two permanent magnets 1 1 of horse shoe form held in place by clamps such as 2 2 preferably of soft iron, said clamps being attached to the magnets by means of screws such as 3 3. As clearly shown in Fig. 4, the magnets 1 1 are spaced apart and it will be understood that the screws 3 3 pass between and not into` the magnets. At their inner ends the screws 3 are threaded and engage pole pieces such as 4- 4 of which two are provided and which project toward each other from the inner into the space threaded faces of the magnets. At their outer ends the screws 3 3 brass yokes such as 5 5, the purposev of which will hereinafter appear. A U-shaped soft 1ron`core6V is screwedv to the .yokes'5 5 intermediate thereof and is surrounded by a coil 7 which is wound transverselyv to 'the plane of Fig. 3.1 The coil 7 'is attached at its two ends to the binding posts 8 8 which ex tend through the box 9 in which the' transmitting and receiving apparatus is mounted. As shown clearly in Fig.` 3, the' separated edges of the channel shaped cored-extend 4 4 and almost tofithe horizontal line connecting the centers of said pole pieces.- Ad# jacent the ends of the core and set approximately on said central line between the ltwo pole pieces, is an armature 10 of soft iron. The armature-l0 is connected to a membrane 11 by means of a bent arm such as 12. The armature 10 is ofsoft iron' but I have discovered that mica is the substance best adapted for use as the membrane 11, since it possesses great 'resilienc and its vibrations are of greater amplitu e than those which can be obtained from a diaphragm of soft iron or steel just as is ordinarily employed, and consequently the volume and clearness of tone given from the mica diaphragm is superior to that receivers or sound reproducers.

The edges of the diaphragm 11 are held between two ring like gaskets of oiled silk 12 12a which gaskets 12a-12 are held between two casings 13 and 14, the casing 14 between the two polel pieces obtainable from previous pass through recesses being somewhat dished and having a threaded tube lwhich projects through and has threaded engagement with the side of the casing 9. .The casing 13 is also. provided with a flange 16 which is interiorly screw and engages a flange on the casing 14. The casing 14 is of annular form and is supported from the magnets 1 1 by means of bolts 17 17 which extend through the space between the' two magnets.

N ow it will be understood that a` magnetic field exists between the pole pieces 4 4 and that the armature 10 will tend to thread itself parallel to the direction of the magnetic field in which it isplaced. Consequently, when the field of theA magnets 1 1 is not disturbed the armature 10 will occupy the position shown in Fig. 3 coinciding with phragm 11 with the production of speech.

As clearly shown in Fig. 4, the armature l0 ispivotally mounted by means of screws 18 which are mounted centrally in two nonmagnetic bars 19 suitably supported at the ends of the flange 2. i

Within the case 9 I rovide also a sensitive transmitter comprlsing a casing 20 of non-conducting material which is supported on the magnet 1 opposite the receiver by means of bolts such as 21--21, which pass between the magnets and carry nuts engaging a suitable yoke 22 of insulating material The interior of the casing 20 is hollowed out to receive a. conducting member 23 preferably of graphite which is held within the casing 21 by means of a bolt such as 24. A ring 25 is threaded to the casing 20 as at 26 and is provided with an inwardly projecting flange as shown at 27 adapted to clamp the diaphragm 28 against the edge of the casing 20. The ring 23 is also threaded as at -29 to receive the end of a cone shaped sound collector 30 which is secured to the casing 9 by a suitable means, the casing being perforated as shown at 31 to permit the sound waves to have free access to the diaphragm 28. The diaphragm 28 is of steel treated with a waterproofvarnish. The chamber between the member 23 and the diaphragm 28 is half filled with granular carbon 32. Connections for the transmitter are made through binding posts 331-331, one of which is connected to the central bolt 24 and the other to the ring 25.

The casing 9 is preferably placed within a horn such as 33a andsupported thereink by any suitable means such as a spider 34 shown in'Figs. 1 and 2. The horn 33a is mounted in a supportingibase or member 35 which is provided with a central aperture 36 through which wires for the transmitting and receiving members maybe introduced.

As clearly shown in Fig. 1, I prefer to mount my combined receiving and transmitting element with the transmitter disposed toward the large end of the horn 33a and I provide a small interior horn such as 37 which may be screw threaded to the tube 15 which directs the sound from the diaphragm 11 to the small lcurved surface at the rear of the horn 33afrom which it is re,

flected around the casing 9 without inter- 1 ference.

It will be understood that while I have shown and described `the preferred form of my invention, various modifications and rearrangements thereof may be made without departing from the spirit of"my invention, and that parts thereo may be used Without utilizing the whole.

I-Iaving thus described my invention, what I claim is 1. In a telephone apparatus in combination, a diaphragm, a casing in which said diaphragm is suitably supported, a permanent magnet, an armature disposed .in the field of said magnet, a connection'between said diaphragm and said armature, a channel or U-shaped member of soft iron .disposed with its edges adjacent said armature and a receiving coil for energizing said channel member.

2. In a telephone apparatusin combination, a diaphragm, a casing in which said 4 `field of said magnet, a connection between said diaphragm and said armature, a channel or U-shaped member of soft iron` disposed with its edges adjacent said armature,

and a coil wound around said channel shaped member and having the wire therein disposed in planes extending transverse to the direction of the magnetic force emanating from said magnet.

3. Ina telephonie apparatus in combination, a horn, and a combined transmitting and receiving unit disposed within said horn, said unit comprising a sensitive transmitter and a loud speaking receiver, said unit and said horn being so arranged that exterior sound waves entering said horn are guided to said transmitter and sound waves admitted from said receiver are directed out of said horn.

4. In a telephonie apparatus in combination, a horn, and aacombined transmitting and receiving unit disposed Within said horn, said unit comprising a sensitive transmitter and a loud speaking receiver, said unit being provided with an outer casing which is provided with oppositely placed apertures one of which is directed toward the mouth of said horn and the other of which is directed toward the small closed4 end of the horn.

5. In a telephonie apparatus in combination, a horn, and a combined transmitting and Areceiving unit supported within said horn intermediate the ends thereof, said unit being provided with an outer casing,

said casing being provided with two oppoture to the small end of said first mentioned y horn.

6. In a telephonic apparatus, in combina- I tion, a horn open at the large end and substantially closed at the other or small end, with a loud-speaking receiver arranged Within the horn to vibrate the air therein in a direction toward the closed end of the horn, and a sensitive transmitter also arranged Within the horn and having its mouth piece directed outwardly toward the open end of the horn, direct sound Waves into the transmitter and to receive and amplify sound Waves from the receiver.

said horn acting to.

7. In a telephonie apparatus, the combination of a horn open at one end and substantially closed at the other, With a sensitive transmitter having a diaphragm and a loudspeaking receiver having a diaphragm arranged Within said horn and intermittent of its ends, the transmitter diaphragm having its surface receiving the sound Waves directed toward the open end of the horn and the-receiver diaphragm having its operative surface for producing sound Waves directed toward the closed end of the horn.

In testimony whereof I afiix my signature in the presence of two Witnesses.

NATHAN A. KURMAN.

Witnesses:

R. CORD, FRANK H. CARTER. 

